Periventricular white matter injury (PWMI) associated with premature birth results in significant suffering to the afflicted and their families and is a major financial burden to society. Appropriate animal models need to be established and refined to serve important tools to understanding the pathogenesis of PWMI and for testing preclinical treatment modalities. Historically, the most prevalent type of PWMI was focal in nature, and thought to be due to rupture of prematurely developed brain blood vessels, local hypoxia and ischemia. The final result was necrotic death of multiple cell types and cystic accumulation in the affected white matter. Recent advances in perinatal care have led to a dramatically increased survival of preterm infants and a significant reduction in focal PWMI. However, the incidence of a diffuse form of PWMI, primarily affecting the myelinating cells of the CNS (oligodendrocytes), has not decreased, and is now the most prevalent type of PWMI leading to motor and cognitive disabilities, occurring in about 45-65% of pre-term births. We have modeled this increasingly- prevalent form of PWMI in mice by inducing injury at a developmental time point at which oligodendrocyte progenitors are most vulnerable. In light of epidemiological data which indicate an association of PWMI with infectious diseases during pregnancy and preterm infants, we have determined that a single systemic inflammatory insult administered at this time of peak vulnerability mimics many of the anatomical and behavioral features of this newly-emerging form of PWMI. We propose here to use this new model to dissect the possible mechanisms of oligodendrocyte damage and white matter loss in PWMI using a transgenic lineage tracing system which labels oligodendrocyte progenitors and their progeny, as well as a conditional knockout mouse in which the astrogliotic response is blocked. PUBLIC HEALTH RELEVANCE: Brain injury, including cerebral palsy and mental retardation is associated with premature birth and results in significant suffering to the afflicted and their families and is a major financial burden to society. As epidemiological studies indicate that a likely cause for this condition is maternal infection, we have established a mouse model which recapitulates the disease, and propose to use the model to determine how maternal infection leads to these defects. The proposed studies are expected to reveal new strategies that will allow the development of both predictors that help identify infants at risk and therapeutic agents reduce the consequences in afflicted children.